In the printing art, type was composed in a galley and a galley proof printed for inspection. Changes in composition, spacing, or other improvements could then be accomplished prior to transferring the set type to the press.
Various means for making use of hand-set type have been developed, and machines were perfected for casting lead in response to an operator actuated keyboard.
With the advent of modern lithographic printing equipment, the photographic process became the means for producing a printing master for large-scale printing, and a direct impression master typed on an office typewriter became the common vehicle for less sophisticated but more rapid composition.
The VariTyper brand strike-on cold type machine was developed to provide typed source material but with the lines justified in the manner of set type. This "cold type" is then produced as lithographic masters by photographic techniques.
A more recent development is the photocomposition technique. A source of font, usually a revolving disc of characters in a photographic negative format, is projected within a light-tight environment upon photosensitive high-speed paper.
The photocomposing machine is capable of projecting columns of any width from one word up to the maximum width of the paper. Maximum width is established by the practical optics which can project from the revolving disc, or the practical distance that the disc can be transported within the housing.
However, not always is a column of the maximum width desired. Therefore, the composer very often will produce long narrow columns and waste the balance of the paper. Then, the column is physically cut into proper useful length and pasted onto a backing sheet in order to produce a multi-column galley.
In order to assure optically pleasing alignment, a rule is used to establish the second and further columns in alignment with the first column when such paste-up technique is used.
Mathematical formulas are a very difficult composition problem in known photocomposition machines.
There are three teaching examples given: (1) A strike-on typing machine; (2) A known photocomposer; and finally, an example (3) using the new structure of this invention. Note that in each example the instructions leave space for the unique symbols such as the integration sign .intg.. These symbols must be by some other means, such as hand artistry, or transfer lettering unless a specific symbol matrix and large print capability is available.